1. Field of the Invention
The present invention relates to a vibration isolating table device for supporting a tool or an instrument, arranged so as not to transmit externally applied vibrations to the tool or the instrument, and particularly to a vibration isolating table device in which even if a support table is moved by an externally applied force, the motion of the support table is immediately stoppod and the support table is held horizontally.
2. Description of Prior Art
Precision measuring instruments such as a microscope, a super-precision balance, or the like, can be easily vibrated not only by an externally applied vibration but also by air flow from an air conditioner, disturbance of air in room caused by breath or speaking sound of surrounding persons, or the like. If such a vibration is applied to such a precision measuring instrument, a maloperation may be generated. Accordingly, it is required to cut off or isolate various kinds of such vibrations. It has been tried to protect such a tool or an instrument from externally applied vibrations in such a manner that the tool or instrument is mounted on a vibration isolating table device. The vibration isolating table device is provided with a base plate supported by an elastic member made of a rubber or a synthetic resin material, a table body on which a tool or an instrument is mounted, and a vibration isolating means such as a magnet, a coil-spring, an air-spring, or the like, mounted on the base plate and for supporting the table body horizontally in the floating state. Accordingly, externally applied vibrations never be transmitted to the table body because the vibrations are cut off or absorbed by the elastic member and the vibration isolating means. However, the table body per se is provided with no means for limiting vibrations or displacement thereof. Therefore, if an external force is applied onto the precision measuring instrument or the table body, the table body may be vibrated or displaced, and it take several seconds, for example, about three seconds, for the table body to be stopped to be in the initial horizontal state through the floating support by the vibration isolating means. Therefore, there has been a disadvantage that in the case where a super-precision measuring instrument or the like was mounted on the table body, it was impossible to perform measurement before the table body was stopped when the table body was vibrated.